CHICAGO (CBS) — As many as 10 sitting Chicago aldermen appear headed into one-on-one runoff elections in April, after falling short of the 50 percent plus one threshold needed to win outright on Tuesday.

And four more aldermanic races in wards where the incumbent is stepping down are headed to runoffs on April 5.

Among veteran aldermen headed to runoffs in two months was Bernard Stone (50th), the council’s oldest alderman, who barely survived a runoff election in 2007, when he won by less than 700 votes.

In the 50th Ward, Stone was in a heated battle with Debra Silverstein, an accountant and wife of the ward’s democratic committeeman and State Sen. Ira Silverstein.

With 98 percent of the vote counted, Stone had about 37 percent of the vote, and Silverstein had about 34 percent. The other three candidates were well behind Stone and Silverstein.

Meantime, in the 25th Ward, Ald. Daniel Solis, the powerful chairman of the City Council’s Zoning Committee, also appeared headed to a runoff.

Solis was being challenged by Ambrosio Medrano Jr., the son of a former alderman convicted of corruption charges, and Cuahutemoc Morfin, vice president of a Pilsen chamber of commerce.

With all precincts reporting, unofficial results had Solis with 49 percent of the vote. Morfin had 28 percent and Medrano had 23 percent, meaning Morfin likely would face Solis in an April runoff.

At least eight other sitting aldermen appeared headed for runoffs late Tuesday, including a cluster of neighboring South Side wards.

The highest profile of those races was in the 20th Ward, where incumbent Ald. Willie Cochran, a former police officer, was facing a challenge from rap artist Che “Rhymefest” Smith and three other candidates.

With 100 percent of precincts reporting, Cochran was leading the field with 46 percent of the vote, while Smith was running second at 20 percent. Both newspapers had endorsed attorney George Davis, who was running in third place with 16 percent.

In the 6th Ward, Ald. Freddrenna Lyle was facing a strong challenge from Roderick Sawyer, the son of Eugene Sawyer, who served as mayor for two years after the death of Harold Washington.

With all of the precincts reporting, Lyle had 45 percent of the vote to Sawyer’s 25 percent. Four other candidates split the rest of the vote.

In the 15th Ward, Ald. Toni Foulkes was facing six challengers and held 44 percent of the vote late Tuesday. Her closest challenger, Raymond Lopez, had 15 percent of the vote.

In the 16th Ward, Ald. JoAnn Thompson was facing eight challengers and was leading the field with 43 percent of the vote. She will face a runoff against challenger Hal Baskin in April.

In the 17th Ward, Ald. LaTasha Thomas was leading a field of seven challengers with 49 percent of the vote. Her closest rival was David Moore, with 19 percent of the vote.

On the West Side, Ald. Sharon Dixon was facing more challengers than any other aldermen, with 18 total candidates in the race, including the man she defeated four years ago, former Ald. Michael Chandler.

With all precincts reporting, Chandler had forced a runoff, with Dixon taking 20 percent of the vote and Chandler taking 13 percent.

On the Northwest Side, in the 36th Ward, Ald. John Rice was headed to a runoff against challenger Nicholas Sposato. Rice led a field of six total candidates, taking 48 percent of the vote, while Sposato took 24 percent.

Finally, newly appointed Ald. Timothy Cullerton – who recently filled the seat left vacant by Tom Allen when he was appointed a Cook County judge – fell just short of winning election outright.

In a field of eight candidates, Cullerton took 48 percent of the vote, while real estate business owner Tom Caravette took 22 percent to force a runoff.

There were also four open races headed to runoff elections.

In the 41st Ward – where the council’s lone Republican, Brian Doherty, is retiring after a failed bid for the state legislature – business owner Mary O’Connor was leading a field of 11 candidates with 30 percent of the vote.

O’Connor will face Maurita Gavin, the woman Doherty endorsed, after Gavin took 25 percent of the vote.

Meantime, the 43rd Ward was home to another hard fought race to replace retiring Ald. Vi Daley. The ward’s Democratic committeeman, Michele Smith, and hospital executive Tim Egan were headed to a runoff.

Smith took 38 percent of the vote in that ward, while Egan took 29 percent. Seven other candidates rounded out the field.